Persistency in suffix trees with applications to string interval problems

Tsvi Kopelowitz, Moshe Lewenstein, Ely Porat

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The suffix tree has proven to be an invaluable indexing data structure, which is widely used as a building block in many applications. We study the problem of making a suffix tree persistent. Specifically, consider a streamed text T where characters are prepended to the beginning of the text. The suffix tree is updated for each character prepended. We wish to allow access to any previous version of the suffix tree. While it is possible to support basic persistence for suffix trees using classical persistence techniques, some applications which can make use of this persistency cannot be solved efficiently using these techniques alone. A collection of such problems is that of queries on string intervals of the text indexed by the suffix tree. In other words, if the text T = t1...tn is indexed, one may want to answer different queries on string intervals, ti...tj , of the text. These types of problems are known as position-restricted and contain querying, reporting, rank, selection etc. Persistency can be utilized to obtain solutions for these problems on prefixes of the text, by solving these problems on previous versions of the suffix tree. However, for substrings it is not sufficient to use the standard persistency. We propose more sophisticated persistent techniques which yield solutions for position-restricted querying, reporting, rank, and selection problems.

Original languageEnglish
Title of host publicationString Processing and Information Retrieval - 18th International Symposium, SPIRE 2011, Proceedings
Pages67-80
Number of pages14
DOIs
StatePublished - 2011
Event18th International Symposium on String Processing and Information Retrieval, SPIRE 2011 - Pisa, Italy
Duration: 17 Oct 201121 Oct 2011

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume7024 LNCS

Conference

Conference18th International Symposium on String Processing and Information Retrieval, SPIRE 2011
Country/TerritoryItaly
CityPisa
Period17/10/1121/10/11

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science

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